1. Field of the Invention
This invention relates generally to rotary transducer or head assemblies, and more particularly, is directed to improved rotary head assemblies for use with automatic tracking systems, for example, in helical scan video tape recorders (HVTRs).
2. Description of the Prior Art
Recently, automatic head tracking systems have been used in HVTRs. Such head tracking systems use a deflectable head mounting assembly on which a magnetic head is mounted for reproducing recorded video signals, and the assembly can be controlled so that the magnetic head scans a video tape alone paths at controllably different angles relative to the length of the video tape. Control of the angle is necessary to keep the magnetic head in accurate alignment with a record track containing the signals to be reproduced, particularly, when the video tape is transported at a speed other than the normal reproduction speed or even when the video tape is stopped for the purpose of still mode reproduction. Thus, such a deflectable head mounting assembly permits maintenance of the required scan angle during so-called special reproduction modes, such as, still, slow, fast and even reverse reproduction modes. Nevertheless, there is a problem with such an assembly which arises because the latter uses a single bi-morph leaf, for example, of piezoelectric ceramic material, with one end of the leaf secured to a rotary member, for example, a rotary portion of the usual tape guide drum, and with the magnetic head being secured to the other end of the leaf. The foregoing bi-morph leaf arrangement is very simple and so long as the deflection angle of the bi-morph leaf is small, good head-to-tape contact is maintained. However, when a more substantial angle of deflection is required, for example, when the video tape is being transported or driven at more than twice the normal reproduction speed or is being transported in the reverse direction, the tape-contacting surface of the magnetic head is no longer aligned with the surface of the video tape and there is consequent deterioration in the quality of the reproduced signal.